McDonald's Corp. will roll out the change early next year in the U.S., where people will be able to pick a salad instead of fries at no extra cost. McDonald's says it already lets customers make such swaps in some countries, such as France.

But now it says it now work to make the options available in 20 of its biggest markets around the world, which represent 85 percent of sales. McDonald's, which has more than 34,000 locations around the world, said the change will be in place in 30 to 50 percent of the areas within the next three years and all the regions by 2020.

The world's biggest hamburger chain made the announcement at the Clinton Global Initiative in New York City, where CEO Don Thompson made an appearance on stage with former President Bill Clinton.

In an interview before the announcement, Thompson said McDonald's is looking at developing other healthy sides that will appeal to customers. He noted that McDonald's could also take the fruits and vegetables it offers in other parts of the world, such as cups of corn and kiwi on a stick, and make them more widely available.

"What is it that customers will choose, and what will they eat?" Thompson said. "What we don't want to do is just put something on the menu and say, hey, we did it. We really want consumption."

McDonald's also announced that it would use packaging to make healthier options more attractive for kids. For example, a side of carrots might come in a more colorful, appealing bag. Parents will still be able to order soda with Happy Meals, but McDonald's says it will only promote milk, juice and water on menu boards and in advertising. All advertising to kids will include a "fun nutrition or children's well-being" message, the company said.

The changes follow an announcement by rival Burger King on Tuesday that it would launch a new crinkle-cut french fry that it says has about 20 percent fewer calories than its regular fries. They also come as McDonald's faces criticism from health advocates who say it promotes bad eating habits. After years of outperforming its rivals, McDonald's is also struggling to shake its fast-food image and keep up with shifting tastes. Late last year, McDonald's reported its first monthly sales decline in nearly a decade and sales performance around the world has been choppy ever since.

To better reflect the way people are eating, McDonald's recently started giving customers the choice to substitute egg whites in all its breakfast sandwiches. It also rolled out chicken wraps, which are partly intended to go after people who want foods they feel are fresher or healthier, and might head to places such as Subway instead.

McDonald's marketing to children is also an ongoing issue. A recent study by the Robert Wood Johnson Foundation, for example, found that the chain's ads targeting children often emphasize toy giveaways and movie tie-ins, rather than food. And at its latest annual shareholders meeting, a 9-year-old girl made headlines after she stood to ask Thompson to stop "tricking" kids into eating the company's food. The girl was with her mother, who was affiliated with Corporate Accountability, which has pressured McDonald's to changes its marketing practices to kids.

The criticism is clearly a sensitive topic for Thompson, who noted that the Alliance for a Healthier Generation was among the first organizations that approached the company to use its "marketing might" to help kids. The group, which is working with McDonald's on its new health goals, was founded by the Clinton Global Initiative and the American Heart Association.

"Others have said, 'McDonald's, don't advertise to kids,'" Thompson said. "We've always felt like, wow, if we had the impact that you think we have, why don't we leverage it to do something great for kids?"

Howell Wechsler, CEO of Alliance for a Healthier Generation, said the commitments made by McDonald's were worked out over the course of more than a year, with many proposals going back and forth between the two parties. He said the final agreement could help change the way people eat over time, given McDonald's enormous reach.

HE WILL RUN FOR RE-ELECTION TO THE HOUSE INSTEAD. NEW AT 11:00, DO YOU WANT FRIES WITH THAT OR DO YOU WANT A SALAD WITH THAT THROWS THE NEW HEALTHIER OPTIONS MCDONALD IS A UNVEILING TONIGHT, SOME EXPERTS ARE NOT COMPLETELY SOLD ON WHAT THE FAST-FOOD CHAIN IS COOK UP. NEWS MOST'S MARY SALADNA IS LIVE TONIGHT IN NOWTON. HEATHER, McDONALD'S ALREADY OFFERS SALADS ON THE MENU. NOTE IT IS PROMISING A ADD A FRUIT AND VEGETABLE YET TO BE NAMED AS ALTERNATIVES TO THE FRIES. STARTING IN 2014, CAN COMPANY THE FRIES WITH THE VALUE MEAL AND HAVE A SALAD INSTEAD. McDONALD'S IS GIVING YOU HEALTHIER MCOPTIONS. I THINK IT IS A GREAT IDEA. GIVING PEOPLE CHOICE. THE FAST-FOOD GIANT ALREADY OFFERS FRESH FRUIT AND VEGETABLES WHEREVER SEAS SUCH AS THE CORN CUP IN SINGAPORE AND KIWI ON A STICK IN ITALY. THE FIRST TIME THEY WILL OFFER NO COST HEALTHY SUBSTITUTES FOR THE FAMOUS TRIES HERE IN THE U.S. I AM BIG FAN OF THE FRIES. I WOULD PROBABLY STICK WITH THE FRIES. CONSIDER THIS. AL BIG MAC WEIGHS IN AT 550 CALORIES. ED AD A LARGE FRY, YOU GOT 1050-CALORIE MEAL. SWITCHING OUT THE FRIES CUTS THAT NEAR LYNN HALF. THE PROBLEM IS TIMCALLY, THE BEV RANGES AND THE SODAS AND THE DENSE MEALS THAT THEY OFFER ARE UNHEALTHY. DR. NICHOLAS IS AN EXPERT ON OBESITY. HE APPLAUD THE CHANGE BUT CAN'T HELP BUT BE SKEPTICAL. HE ADVICES TO MAKE FAST-FOOD THE EXCEPTION IN THE DIET NOT THE ROUTINE. I RECOMMEND PEOPLE LIMIT IT AS MUCH AS POSSIBLEMENT IF THEY DO GO TO THE REST RENT TO TRY TO BE RESPONSIBLE ABOUT THEIR OPTION. IN ADDITION TO OFFERING HEALTHY SIDES AT NO EXTRA COST. MCDONALD'S WILL ARE OUT NEW PACK AGE FOR THE HEALTHIER OPTION AND PROMOTE MILL BE, JUICE AND WATER ON THE MENUS. NOW THE MOVE COMES AS THE BASE IS BEING CRITICIZED. IT PROMOTES BAD EATING HABIT.

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